The present patent application is filed under 35 U.S.C. 371 for International Application PCT/EPO1/02731, filed Mar. 12, 2001, which was published in German as International Patent Publication WO 01/72719 on Oct. 4, 2001, which is entitled to the right of priority of German Patent Application DE 100 14 607.4, filed Mar. 24, 2000.
The invention relates to a novel process for preparing known asymmetric 4,6-bis(aryloxy)pyrimidine derivatives.
Asymmetric 4,6-bis(aryloxy)pyrimidine derivatives are known and are used, for example, as pesticides in crop protection (cf. WO 94/02470, WO 97/27189, WO 98/21189, WO 99/57116).
The preparation of asymmetric 4,6-bis(aryloxy)pyrimidine derivatives is more difficult than the preparation of symmetric 4,6-bis(aryloxy)pyrimidine compounds since the different aryloxy groups have to be introduced in separate reactions.
A plurality of processes for preparing asymmetric 4,6-bis(aryloxy)pyrimidine derivatives has already been disclosed.
WO 94/02470 describes the preparation of asymmetric 4,6-bis(aryloxy)pyrimidine derivatives by a two-step process. Reaction of 4,6-dichloropyrimidine (A) with one equivalent of a phenol derivative (B) under basic reaction conditions and subsequent reaction with a second phenol derivative (D) gives asymmetric 4,6-bis(aryloxy)pyrimidine derivatives (E) (cf. Scheme 1). 
This process has the disadvantage that an exchange of the aryloxy groups takes place in the second reaction step, giving a product mixture of asymmetric 4,6-bis(aryloxy)pyrimidine derivatives (E) and the symmetric 4,6-bis(aryloxy)pyrimidine derivatives (F) and (G).
As a consequence, the asymmetric 4,6-bis(aryloxy)pyrimidine derivatives (E) are obtained in poor yield and can only be isolated by complicated separation methods.
To avoid the problem of the exchange of the aryloxy groups to the second reaction step, it is possible to use the starting material 4,6-difluoropyrimidine (cf. Scheme 2 and WO 94/02470, EP-A1-794 177). 
However, this process has the disadvantage that 4,6-difluoropyrimidine has to be prepared by a chlorine/fluorine exchange, starting from 4,6-dichloro-pyrimidine. The preparation of asymmetric 4,6-bis(aryloxy)pyrimidine derivatives therefore requires an additional reaction step. Preferred starting materials are therefore 4,6-dichloropyrimidine or 4,6-dichloropyrimidine derivatives.
The preparation of asymmetric 4,6-bis(aryloxy)pyrimidine derivatives starting from 4,6-dichloro-5-halogeno-pyrimidine analogously, to the process described in WO 94/02470 is described in WO 98/41513.
EP-A1-794 177, U.S. Pat. Nos. 5,849,910 and 5,977,363 describe a further process for preparing asymmetric 4,6-bis(aryloxy)pyrimidine derivatives (E) starting from 4,6-dichloropyrimidine (A) (cf. Scheme 3). 
In this process, the aryloxy-chloropyrimidine derivative (C) obtained after the first reaction step is treated with at least one molar equivalent of a tertiary amine.
The intermediates formed are pyrimidinyl-ammonium derivatives (J), which are reacted with phenol derivatives (D) to give asymmetrical 4,6-bis(aryloxy)pyrimidine derivatives (E).
This process has the disadvantage that at least equivalent molar amounts of the tertiary amine are required, which can only be recovered using complicated procedures. Moreover, the asymmetric 4,6-bis(aryloxy)pyrimidine derivatives are only obtained in moderate yields. This process is therefore unsuitable for the large-scale industrial preparation, especially if expensive amines are used.
It has now been found that asymmetric 4,6-bis(aryloxy)pyrimidine derivatives of the general formula (I), 
in which
Ar1 represents in each case substituted or unsubstituted aryl or heterocyclyl,
X represents hydrogen, fluorine, chlorine or bromine,
L1, L2, L3, L4 and L5 are identical or different and independently of one another each represents hydrogen, halogen, cyano, nitro, alkylcarbonyl formyl, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, in each case optionally halogen-substituted alkyl, alkoxy, alkylthio, alkylsulphinyl or alkylsulphonyl, or
L1, L2, L3 and L4 are identical or different and independently of one another each represents hydrogen, halogen, cyano, nitro, alkylcarbonyl, formyl, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, in each case optionally halogen-substituted alkyl, alkoxy, alkylthio, alkylsulphinyl or alkylsulphonyl, and
L5 represents one of the groups below: 
where * denotes the point of attachment to the phenyl radical, and where the radicals 
are different,
are obtained when
4,6-dichloropyrimidine derivatives of the general formula (II), 
in which
X is as defined above,
a) are initially, in a first step, reacted with compounds of the general formula (III),
Ar1xe2x80x94OH,xe2x80x83xe2x80x83(III)
xe2x80x83in which
Ar1 is as defined above,
if appropriate in the presence of a diluent and if appropriate in the presence of an acid acceptor,
and the resulting compounds of formula (IV), 
in which
Ar1 and X are each as defined above
are then, in a second step, reacted with compounds of the general formula (V), 
in which
L1, L2, L3, L4 and L5 are each as defined above,
if appropriate in the presence of a solvent, if appropriate in the presence of a base and with addition of from 2 to 40 mol % of 1,4-diazabicyclo[2.2.2]octane (DABCO), or
b) are initially, in a first step, reacted with compounds of the general formula (V), 
in which
L1, L2, L3, L4 and L5 are each as defined above,
if appropriate in the presence of a diluent and if appropriate in the presence of an acid acceptor,
and the resulting compounds of the formula (VI), 
in which
X, L1, L2, L3, L4 and L5 are each as defined above,
are then, in a second step, reacted with compounds of general formula (III),
Ar1xe2x80x94OH,xe2x80x83xe2x80x83(III)
in which
Ar1 is as defined above,
if appropriate in the presence of a solvent, if appropriate in the presence of a base and with addition of from 2 to 40 mol % of 1,4-diazabicyclo[2.2.2]octane (DABCO).
In the definitions, the saturated or unsaturated hydrocarbon chains, such as alkyl, alkanediyl, alkenyl or alkinyl, are in each case straight-chain or branched, including in combination with heteroatoms, such as, for example, in alkoxy, alkylthio or alkylamino. Unless indicated otherwise, preference is given to hydrocarbon chains having 1 to 6 carbon atoms. Unless indicated otherwise, hydrocarbon chains having 2 to 6 carbon atoms are preferred for alkenyl or alkinyl.
Halogen generally represents fluorine, chlorine, bromine or iodine, preferably fluorine, chlorine or bromine, in particular fluorine or chlorine.
Aryl represents aromatic, mono- or polycyclic hydrocarbon rings, such as, for example, phenyl, naphthyl, anthranyl, phenanthryl, preferably phenyl or naphthyl, in particular phenyl.
Heterocyclyl represents saturated or unsaturated, and also aromatic, cyclic compounds where at least one ring member is a heteroatom, i.e. an atom different from carbon. If the ring contains a plurality of heteroatoms, this can be identical or different. Preferred heteroatoms are oxygen, nitrogen or sulphur. If the ring contains a plurality of oxygen atoms, these are adjacent. If appropriate, the cyclic compounds form a polycyclic ring system together with other carbocyclic or heterocyclic, fused-on or bridged rings. Preference is given to mono- or bicyclic ring systems, in particular to mono- or bicyclic aromatic ring systems.
Cycloalkyl represents saturated carbocyclic compounds which, if appropriate, form a polycyclic ring system together with other carbocyclic fused-on or bridged rings.
A polycyclic ring system can be attached to a heterocyclic ring or a fused-on carbocyclic ring. This heterocyclyl group can also be mono- or polysubstituted, preferably by methyl, ethyl or halogen. Preference is given to mono- or bicyclic ring systems, in particular mono- or bicyclic aromatic ring systems.
Halogenoalkoxy represents partially or fully halogenated alkoxy. In the case of polyhalogenated halogenoalkoxy, the halogen atoms can be identical or different. Preferred halogen atoms are fluorine and chlorine, in particular fluorine. If the halogenoalkoxy additionally carries other substituents, the maximum number of halogen atoms possible is reduced to the remaining free valencies. Unless indicated otherwise, preference is given to hydrocarbon chains having 1 to 6 carbon atoms.
Halogenoalkyl represents partially or fully halogenated alkyl. In the case of polyhalogenated halogenoalkyl, the halogen atoms can be identical or different. Preferred halogen atoms are fluorine and chlorine, in particular fluorine. If the halogenoalkyl additionally carries other substituents, the maximum number of halogen atoms possible is reduced to the remaining free valencies. Unless indicated otherwise, preference is given to hydrocarbon chains having 1 to 6 carbon atoms.
The starting materials of the formulae (III) and (V), the intermediates of the formulae (IV) and (VI) and the end products of the general formula (I) can be present as pure isomers of different possible isomeric forms, for example E or Z isomers or, as appropriate, as mixtures of different possible isomeric forms, in particular of heteroisomers, such as for example, E/Z mixtures.
In general, Ar1 represents, in particular:
heterocyclyl having 3 to 7 ring members which is optionally substituted by halogen or by alkyl, alkoxy, halogenoalkyl, halogenoalkoxy having in each case 1 to 4 carbon atoms;
or represents phenyl or naphthyl, each of which is optionally mono- to tetrasubstituted by identical or different substituents, the possible substituents preferably being selected from the list below:
halogen, cyano, nitro, formyl, carboxyl, carbamoyl, thiocarbamoyl;
in each case straight-chain or branched alkyl, oxoalkyl, alkoxy, alkoxyalkyl, alkylthioalkyl, dialkoxyalkyl, alkylthio, alkylsulphinyl or alkylsulphonyl having in each case 1 to 8 carbon atoms;
in each case straight-chain or branched alkenyl or alkenyloxy having in each case 2 to 6 carbon atoms;
in each case straight-chain or branched halogenoalkyl, halogenoalkoxy, halogenoalkylthio, halogenoalkylsulphinyl or halogenoalkylsulphonyl having
in each case 1 to 6 carbon atoms and 1 to 13 identical or different halogen atoms;
in each case straight-chain or branched halogenoalkenyl or halogenoalkenyloxy having in each case 2 to 6 carbon atoms and 1 to 11 identical or different halogen atoms;
in each case straight-chain or branched dialkylamino;
alkylcarbonyl, alkylcarbonyloxy, alkoxycarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, arylalkylaminocarbonyl, dialkylaminocarbonyloxy, alkenylcarbonyl or alkinylcarbonyl, having 1 to 6 carbon atoms in the respective hydrocarbon chain;
cycloalkyl or cycloalkyloxy having in each case from 3 to 6 carbon atoms;
in each case doubly attached alkylene having 3 or 4 carbon atoms, oxyalkylene having 2 or 3 carbon atoms or dioxyalkylene having 1 or 2 carbon atoms, each of which is optionally mono- to tetrasubstituted by identical or different substituents from the group consisting of fluorine, chlorine, oxo, methyl, trifluoromethyl and ethyl;
or a grouping 
in which
A1 represents hydrogen, hydroxyl or alkyl having 1 to 4 carbon atoms or cycloalkyl having 1 to 6 carbon atoms and
A2 represents hydroxyl, methoxy, ethoxy, amino, methylamino, phenyl, benzyl or represents in each case optionally cyano-, alkoxy-, alkylthio-, alkylamino-, dialkylamino- or phenyl-substituted alkyl or alkoxy having 1 to 4 carbon atoms, or represents alkenyloxy or alkinyloxy having in each case 2 to 4 carbon atoms, and also phenyl, benzoyl, benzoylethenyl, cinnamoyl, heterocyclyl or phenylalkyl, phenylalkyloxy or heterocyclylalkyl, having in each case 1 to 3 carbon atoms in the respective alkyl moieties and being in each case optionally mono- to trisubstituted in the ring moiety by halogen and/or straight-chain or branched alkyl or alkoxy having 1 to 4 carbon atoms.
Preference is given to compounds in which Ar1 represents:
optionally methyl-, ethyl-, methoxy-, ethoxy-, trifluoromethyl- or trifluoromethoxy-substituted thienyl, pyridyl or furyl;
or represents phenyl which is in each case optionally mono- to tetrasubstituted by identical or different substituents, the possible substituents preferably being selected from the list below:
fluorine, chlorine, bromine, iodine, cyano, nitro, formyl, carboxyl, carbamoyl, thiocarbamoyl,
methyl, ethyl, n- or i-propyl, n-, i-, s- or t-butyl, 1-, 2-, 3-, neo-pentyl, 1-, 2-, 3-, 4-(2-methylbutyl), 1-, 2-, 3-hexyl, 1-, 2-, 3-, 4-, 5-(2-methylpentyl), 1-, 2-, 3-(3-methylpentyl), 2-ethylbutyl, 1-, 3-, 4-(2,2-dimetylbutyl), 1-, 2-(2,3-dimethylbutyl), 3-oxobutyl, methoxymethyl, dimethoxymethyl,
methoxy, ethoxy, n- or i-propoxy,
methylthio, ethylthio, n- oder i-propylthio, methylsulphinyl, ethylsulphinyl, methylsulphonyl or ethylsulphonyl,
vinyl, allyl, 2-methylallyl, propene-1-yl, crotonyl, propargyl, vinyloxy, allyloxy, 2-methylallyloxy, propene-1-yloxy, crotonyloxy, propargyloxy, trifluoromethyl, trifluoroethyl,
difluoromethoxy, trifluoromethoxy, difluorochloromethoxy, trifluoroethoxy, difluoromethylthio, trifluoromethylthio, difluorochloromethylthio, trifluoromethylsulphinyl or trifluoromethylsulphonyl, dimethylamino, diethylamino,
acetyl, propionyl, methoxycarbonyl, ethoxycarbonyl, methylaminocarbonyl, ethylaminocarbonyl, dimethylaminocarbonyl, diethylaminocarbonyl, dimethylaminocarbonyloxy, diethylaminocarbonyloxy, benzylaminocarbonyl, acryloyl, propioloyl, cyclopentyl, cyclohexyl,
in each case doubly attached propanediyl, ethyleneoxy, each of which is optionally mono- to tetrasubstituted by identical or different substituents from the group consisting of fluorine, chlorine, oxo, methyl and trifluoromethyl,
or a grouping 
where
A1 represents hydrogen, methyl of hydroxyl and
A2 represents hydroxyl, methoxy, ethoxy, amino, methylamino, phenyl or benzyl, and also phenyl, benzoyl, benzoylethenyl, cinnamoyl, benzyl, phenylethyl, phenylpropyl, benzyloxy, 5,6-dihydro-1,4,2-dioxazin-3-ylmethyl, triazolylmethyl, benzoxazol-2-ylmethyl, 1,3-dioxan-2-yl, benzimidazol-2-yl, dioxol-2-yl, oxadiazolyl, each of which is optionally mono- to trisubstituted in the ring moiety by halogen and/or straight-chain or branched alkyl or alkoxy having 1 to 4 carbon atoms.
In a further very particularly preferred group of compounds, Ar1 represents mono- to tetrasubstituted phenyl, where the substituents are selected from the list below:
halogen, cyano, in each case straight-chain or branched alkyl or halogenoalkyl having in particular 1 to 4 carbon atoms.
In general, X represents, in particular, fluroine or chlorine.
Particular preference is given to compounds in which X represents fluorine.
In general, L1, L2, L3, L4 and L5 are identical or different and independently of one another each represents in particular hydrogen, halogen, cyano, nitro, formyl, alkylcarbonyl, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl having in each case 1 to 6 carbon atoms, alkyl, alkoxy, alkylthio, alkylsulphinyl or alkylsulphonyl having in each case 1 to 6 carbon atoms and being in each case optionally substituted by 1 to 5 halogen atoms, or
L1, L2, L3 and L4 are identical or different and independently of one another each represents in particular hydrogen, halogen, cyano, nitro, formyl, alkylcarbonyl, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl having in each case 1 to 6 carbon atoms, alkyl, alkoxy, alkylthio, alkylsulphinyl or alkylsulphonyl having in each case 1 to 6 carbon atoms and being in each case optionally substituted by 1 to 5 halogen atoms and
L5 represents in particular one of the groups below: 
where * denotes the point of attachment to the phenyl radical.
Preference is given to compounds in which L1, L2, L3 and L4 are identical or different and independently of one another each preferably represents hydrogen, fluorine, chlorine, bromine, cyano, nitro, acetyl, propionyl, methoxycarbonyl, ethoxycarbonyl, methylaminocarbonyl, ethylaminocarbonyl, dimethylaminocarbonyl, diethylaminocarbonyl, methyl, ethyl, n- or i-propyl, n-, i-, s- or t-butyl, methoxy, ethoxy, n- or i-propoxy, methylthio, ethylthio, methylsulphinyl, ethylsulphinyl, methylsulphonyl or ethylsulphonyl, trifluoromethyl, trifluoroethyl, difluoromethoxy, trifluoromethoxy, difluorochloromethoxy, trifluoroethoxy, difluoromethylthio, difluorochloromethylthio, trifluoromethylthio, trifluoromethylsulphinyl or trifluoromethylsulphonyl.
In a very particularly preferred group of compounds, L1, L2, L3 and L4 each represent hydrogen or methyl.
In a further very particularly preferred group of compounds, L1, L2, L3 and L4 each represent hydrogen.
Preference is given to compounds in which L5 represents one of the groups below: 
where * denotes the point of attachment to the phenyl radical.
In a very particularly preferred group of compounds, L5 represents one of the groups below: 
where * denotes the point of attachment to the phenyl radical.
The abovementioned general or preferred radical definitions apply both to the end products of the formula (I) and, correspondingly, to the starting materials or intermediates required in each case for the preparation.
Independently of the combination of radicals given in each case, the definitions of radicals given in the combinations or preferred combinations of radicals in question specifically for these radicals can also be replaced by any definitions of radicals of other preferred ranges.
It is extremely surprising that, in the process according to the invention, aryloxyhalogenopyrimidine derivatives react with high selectivity and yield to give asymmetric 4,6-bis(aryloxy)pyrimidine derivatives when from 2 to 40 mol % of the tertiary amine 1,4-diazabicyclo[2.2.2]octane (DABCO) are added. Since it is mentioned in the prior art (cf. EP-A1-794 177, U.S. Pat. Nos. 5,849,990 and 5,977,363) that this reaction requires at least a molar equivalent of a tertiary amine, it is extremely surprising that this reaction can also be carried out with from 2 to 40 mol % of DABCO, giving excellent yields. This is confirmed by a comparative experiment in which the reaction was carried out without addition of DABCO (cf. Example 4, second step). The product can only be isolated in very poor yields.
The process according to the invention has a number of advantages. The asymmetric 4,6-bis(aryloxy)pyrimidine derivatives are obtained in high yields and purities. Moreover, it is possible to use, as starting materials, 4,6-difluoropyrimidine derivatives, which are easier to obtain than 4,6-dichloropyrimidine derivatives. Traditionally, it is not necessary to recover the amine, since only catalytic amounts of DABCO are needed for carrying out the process.
The compounds of the formula (II) required as starting materials for carrying out the process according to the invention are known and can be prepared by known methods (cf. DE-A1-197 10 609, WO 97/49605, DE-A1-196 42 533 and DE-A1-195 31299) or are commercially available products.
The compounds of the formula (III) required as starting materials for carrying out the process according to the invention are customary commercial products or can be prepared from the latter by simple processes.
The compounds of the formula (V) required as starting materials for carrying out the process according to the invention are known and can be prepared by known methods (cf. DE-A1 196 11 653, WO-A-95/24396, WO 95/04728, WO 97/27189, WO 97/14687, WO 98/23155, WO 98/21189, WO 98/55461, WO 99/09026, WO 99/57116). All other starting materials are customary commercial products or can be prepared from the latter by simple processes.
Suitable diluents for carrying out the first step of the process according to the invention are all inert organic solvents. These include, by way of example and by way of preference, aliphatic, alicyclic or aromatic hydrocarbons, such as, for example, petroleum ether, hexane, heptane, cyclohexane, methylcyclohexane, benzene, toluene, xylene or decalin; halogenated hydrocarbons, such as, for example, chlorobenzene, dichlorobenzene, dichloromethane, chloroform, carbon tetrachloride, dichloroethane or trichloroethane; ethers, such as, for example, diethyl ether, diisopropyl ether, methyl-t-butyl ether, methyl-t-amyl ether, dioxane, tetrahydrofuran, 1,2-dimethoxyethane, 1,2-diethoxyethane or anisole; ketones, such as, for example, acetone, butanone, methyl isobutyl ketone or cyclohexanone, nitriles, such as, for example, acetonitrile, propionitrile, n- or i-butyronitrile or benzonitrile, amides, such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methylformamide, N-methylpyrrolidone or hexamethylphosphoric triamide; esters, such as methyl acetate or ethyl acetate; sulphoxides, such as dimethyl sulphoxide, sulphones, such as sulpholane; or mixtures thereof with water. In the first step of the process according to the invention, preference is given to using ketones, in particular methyl isobutyl ketone.
The first step of the process according to the invention is, if appropriate, carried out in the presence of a suitable acid acceptor. Suitable acid acceptors are all customary inorganic or organic bases. These include, by way of example and by way of preference, alkaline earth metal or alkali metal hydroxides, acetates, carbonates or bicarbonates, such as, for example, sodium hydroxide, potassium hydroxide, sodium acetate, potassium acetate, sodium carbonate, potassium carbonate, potassium bicarbonate or sodium bicarbonate; tertiary amines, such as, for example, trimethylamine, triethylamine, tributylamine, N,N-dimethylaniline, N,N-dimethylbenzylamine, pyridine, N-methylpiperidine, N-methylmorpholine, N,N-dimethylaminopyridine, diazabicyclononene (DBN) oir diazabicycloundecene (DBU); and also alkaline earth metal or alkali metal hydrides, such as, for example, calcium hydride, sodium hydride or potassium hydride. In the first step of the process according to the invention, preference is given to using alkaline earth metal or alkalimetal carbonates, in particular potassium carbonate or sodium carbonate.
In the first step of the process according to the invention, the reaction temperatures can be varied within a relatively wide range. In general, the reaction is carried out at temperatures from 0xc2x0 C. to 100xc2x0 C., preferably at temperatures from 40xc2x0 C. to 80xc2x0 C.
For carrying out the process according to the invention, in general from 1 to 4 mol, preferably from 1 to 1.1 mol, of the 4,6-dichloropyrimidine derivatives of the formula (II) are employed per mole of the compounds of the formula (III).
For carrying out the process according to the invention, in general from 1 to 4 mol, preferably from 1 to 1.1 mol, of the 4,6-dichloropyrimidine derivatives of the formula (II) are employed per mole of the compounds of the formula (V).
For carrying out the first step of the process according to the invention, the following procedure is generally adopted. The 4,6-dichloropyrimidine derivative of the formula (II) is, if appropriate in the presence of a diluent, admixed with a base. The compound of the formula (III) or the compound of the formula (V) is added, if appropriate in the presence of a diluent, and the mixture is, if appropriate at elevated or at radius temperature, stirred until the reaction has gone to completion. After the reaction has ended, the reaction mixture is worked up in a customary manner or reacted directly in situ in the second step of the process according to the invention.
The addition of compounds of the formula (III) or of compounds of the formula (V), if appropriate in the presence of diluent, in the first step of the process according to the invention is carried out, in particular, by metered addition to compounds of the formula (II) dissolved, if appropriate, in a ketone, in particular in methyl isobutyl ketone. The addition is carried out all at once or within a period of 12 hours, preferably all at once or within a period of 6 hours.
Suitable diluents for carrying out the second step of the process according to the invention are all inert organic solvents. These include, by way of example and by way of preference, aliphatic, alicyclic or aromatic hydrocarbons, such as, for example, petroleum ether, hexane, heptane, cyclohexane, methylcyclohexane, benzene, toluene, xylene or decalin; halogenated hydrocarbons, such as, for example, chlorobenzene, dichlorobenzene, dichloromethane, chloroform, carbon tetrachloride, dichloroethane or trichloroethane; ethers, such as, for example, diethyl ether, diisopropyl ether, methyl-t-butyl ether, methyl-t-amyl ether, dioxane, tetrahydrofuran, 1,2-dimethoxyethane, 1,2-diethoxyethane or anisole; ketones, such as, for example, acetone, butanone, methyl isobutyl ketone or cyclohexanone, nitrites, such as, for example, acetonitrile, propionitrile, n- or i-butyronitrile or benzonitrile, amides, such as N,N-dimethylformanilide, N,N-dimethylacetamide, N-methylformanilide, N-methylpyrrolidone or hexamethylphosphoric triamide; esters, such as methyl acetate or ethyl acetate; sulphoxides, such as dimethyl sulphoxide, sulphones, such as sulpholane; or mixtures thereof with water. In the second step of the process according to the invention, preference is given to using ketones, in particular methyl isobutyl ketone.
The second step of the process according to the invention is, if appropriate, carried out in the presence of a suitable acid acceptor. Suitable acid acceptors are all customary inorganic or organic bases. These include, by way of example and by way of preference, alkaline earth metal or alkali metal hydroxides, acetates, carbonates or bicarbonates, such as sodium hydroxide, potassium hydroxide, sodium acetate, potassium acetate, sodium carbonate, potassium carbonate, potassium bicarbonate or sodium bicarbonate; and also alkaline earth metal or alkali metal hydrides, such as, for example, calcium hydride, sodium hydride or potassium hydride. In the second step of the process according to the invention, preference is given to using alkaline earth metal or alkali metal carbonates, in particular potassium carbonate or sodium carbonate.
The second step of the process according to the invention is carried out in the presence of catalytic amounts of 1,4-diazabicyclo[2.2.2]octane (DABCO).
When carrying out the second step of the process according to the invention, the reaction temperatures can be varied within a relatively wide range. In general, the reaction is carried out at temperatures of from 0xc2x0 C. to 100xc2x0 C., preferably at temperatures of from 40xc2x0 C. to 90xc2x0 C., in particular at temperatures of from 50xc2x0 C. to 80xc2x0 C.
For carrying out the process according to the invention, in general from 0.8 to 4 mol, preferably from 0.95 to 1.05 mol, of the compounds of the formula (V) are employed per mole of the compounds of the formula (IV).
For carrying out the process according to the invention, in general from 0.8 to 4 mol, preferably from 0.95 to 1.05 mol, of the compounds of the formula (III) are employed per mole of the compounds of the formula (VI).
For carrying out the process according to the invention, in general from 2 to 40 mol %, preferably from 2 to 20 mol %, of 1,4-diazabicyclo[2.2.2]octane are employed per mole of the compounds of formula (IV).
For carrying out the process according to the invention, in general from 2 to 40 mol %, preferably from 2 to 20 mol %, of 1,4-diazabicyclo[2.2.2]octane are employed per mole of the compounds of formula (VI).
The second step of process variant a) is generally carried out as follows. The compounds of the formula (V) are, if appropriate in the presence of a diluent, admixed with a base and 1,4-diazabicyclo[2.2.2]octane. The compounds of the formula (IV) are added, if appropriate in the presence of the diluent, and the mixture is stirred, if appropriate at elevated temperature. After the reaction has ended, the reaction mixture is worked up in a customary manner.
Alternatively, the second step of process variant a) can also be carried out by admixing the compounds of the formula (IV), if appropriate in the presence of a diluent, with a base and 1,4-diazabicyclo[2.2.2]octane. The compounds of the formula (V) are added, if appropriate in the presence of a diluent, and the mixture is stirred, if appropriate at elevated temperature. After the reaction has ended, the reaction mixture is worked up in a customary manner.
The second step of process variant b) is generally carried out as follows. The compounds of the formula (III) are, if appropriate in the presence of a diluent, admixed with a base and 1,4-diazabicyclo[2.2.2]octane. The compounds of the formula (VI) are added, if appropriate in the presence of the diluent, and the mixture is stirred, if appropriate at elevated temperature. After the reaction has ended, the reaction mixture is worked up in a customary manner.
Alternatively, process step b) can also be carried out by admixing the compounds of the formula (VI), if appropriate in the presence of a diluent, with a base and 1,4-diazabicyclo[2.2.2]octane. The compounds of the formula (III) are added, if appropriate in the presence of a diluent, and the mixture is stirred, if appropriate at elevated temperature. After the reaction has ended, the reaction mixture is worked up in a customary manner. In a specific variant, the process according to the invention is carried out as a one-pot reaction.
The examples below serve to illustrate the invention. However, the invention is not limited to the examples.